Vascular Flashcards

Question

Carotid Artery Disease also known as?

Answer 1

Carotid Artery Stenosis

Answer 2

Patients with transient ischemic attack (TIA) or mild stroke who have 70-99% stenosis in the carotid artery. Some cases with 50-69% stenosis, if there are high stroke risk factors.

Answer 3

CEA is usually recommended within two weeks of a TIA or minor stroke to prevent further events.

Answer 4

Asymptomatic Carotid Artery Stenosis: CEA may be considered in patients with 60-99% stenosis even without symptoms, especially in those under 75 years old and in good health. The decision is influenced by the patient's overall health, life expectancy, and the skill and experience of the surgical team.

Answer 5

Usually caused by embolization Manifests as amaurosis fugax, paresthesia, clumsiness of extremities, speech problems Carotid duplex ultrasonography > Duplex ultrasound is the primary noninvasive diagnostic tool for detecting, grading and monitoring of carotid artery stenosis due to its low cost, high resolution, and widespread availability. Sensitivity & specificity to detect stenosis >60% - approximately 94%

Answer 6

painless loss of vision in 1 eyes refers to a transient monocular visual loss, is considered a medical emergency. Usually caused by atherosclerotic emboli that leads to retinal artery occlusion, or other conditions, such as inflammation of the associated nerves and arteries

Answer 7

imaging test uses X rays visualize carotid arteries inject contrast dye into groin or arm catheter take images ==> identify stenosis (narrowing), blockages.

Answer 8

Carotid and vertebral arteries

Answer 9

brain and face

Answer 10

in the neck and from the brachiocephalic artery

Answer 11

in the thorax from the arch of the aorta

Answer 12

bifurcate: in the NECK at the level of: CAROTID SINUS

Answer 13

into the internal carotid artery (ICA), which supplies the brain the external carotid artery (ECA), which supplies the neck and face

Answer 14

Carotid sinus or the upper border of the thyroid cartilage (typically at the level of the fourth or fifth cervical vertebra)

Answer 15

serves as a point for the location of the "carotid body," a chemoreceptor and the "carotid sinus," a baroreceptor. CHEMORECEPTOR = CAROTID BODY BARORECEPTOR = CAROTID SINUS

Answer 16

is sensitive to: decreased PO2 increased PCO2 decreased pH of blood ==> responsible for alerting the brain to change the respiratory rate.

Answer 17

respond to changes in the stretch of the blood vessel and are responsible for detecting changes and maintaining blood pressure. (bezold Jerish reflex)

Answer 18

Main effects: Bradycardia, hypotension, and coronary vasodilation Trigger: Decreased preload (less venous return → underfilled left ventricle) Mechanism: Receptors in the left ventricle (both chemo- and mechanoreceptors) sense poorly filled or contracting ventricle This activates the Bezold–Jarisch reflex Leads to inhibition of the sympathetic nervous system (SNS) and activation of the parasympathetic nervous system (PSNS) Result: → Bradycardia, hypotension, and coronary artery dilation

Answer 19

a small dilated area located at the bifurcation of the common carotid artery, where it splits into the internal and external carotid arteries. It contains baroreceptors, which are specialized sensors that detect changes in blood pressure.

Answer 20

1. The baroreceptors in the carotid sinus are sensitive to the stretch of the arterial wall, which corresponds to blood pressure. 2. When blood pressure increases, these receptors are stretched more, sending signals to the brain (specifically, the medulla oblongata) via the glossopharyngeal nerve (cranial nerve IX). ==> Reduces Sympathetic Nervous System activity and increase PSNS. Slow HR, dilates blood vessles, decrease BP 3. When blood pressure drops, the signals from these receptors decrease. Causes SNS acitivty increase > vasoconstriction > increase HR and BP

Answer 21

Cerebral autoregulation is the brain's intrinsic ability to maintain stable blood flow across a range of blood pressures, protecting the brain from ischemia or hyperperfusion. The brain's blood vessels can constrict or dilate in response to changes in systemic blood pressure. when blood pressure increases, cerebral vessels constrict to reduce blood flow. When blood pressure decreases, vessels dilate to increase blood flow.

Answer 22

because of cerebrovascular autoregulation

Answer 23

CPP = MAP-ICP (or CVP, which ever is higher)

Answer 24

RIGHT require a higher MAP

Answer 25

In patients with conditions like hypertension, diabetes, or atherosclerosis, the range and effectiveness of autoregulation may be reduced. These patients may have a narrower range of MAP within which their brain can effectively autoregulate. During surgeries like CEA, cerebral autoregulation may be temporarily disrupted, making patients more vulnerable to ischemic events or hyperperfusion injury if blood pressure is not carefully controlled.

Answer 26

sensing and regulating blood pressure through baroreceptors. High BP → increased stretch → increased baroreceptor firing → activates parasympathetic system → ↓ HR, ↓ contractility, ↓ BP Low BP → decreased stretch → decreased baroreceptor firing → activates sympathetic system → ↑ HR, ↑ contractility, ↑ vasoconstriction, ↑ BP

Answer 27

transient or lasting baroreceptor dysfunction, resulting in labile blood pressure.

Answer 28

CEA necessitating meticulous blood pressure management to protect brain health.

Answer 29

Protection of heart and brain from ischemic injury Control HR and arterial blood pressure Ask surgeon acceptable BP range Know preop BP Ablate surgical pain and stress responses *** have an awake patient at the conclusion of surgery for immediate neurological examination!

Answer 30

neurological examination

Answer 31

ECG monitors II, V5 Watch for ST segment changes Radial Arterial Line NIBP contra lateral arm Two large bore peripheral IVs Stopcocks placed close to patient port for medication gtts IVAC pumps Eye protection

Answer 32

Propofol - induction Fentanyl – small amts Etomidate - induction NDMR Beta blocker (esmolol) Vasopressors Inhaled volatile agents Remifentanil; dexmedetomidine ACT machine/LR cuvettes in OR

Answer 33

must maintain Arterial Blood Pressure 10% ABOVE baseline

Answer 34

Head foams NO PILLOWS

Answer 35

Phenylephrine, norepinephrine ephedrine (supply and demand mismatch; know your drugs

Answer 36

BP nitroglycerin, Nipride, Nicardipine

Answer 37

Surgical manipulation of carotid sinus with activation of baroreceptor reflexes Causes abrupt bradycardia and hypotension

Answer 38

Stop surgical manipulation Infiltrate carotid bifurcation w 1% lidocaine This can help blunt reflex

Answer 39

Stump Pressure is the pressure measured in the internal carotid artery (ICA) distal to the surgical clamp during carotid endarterectomy (CEA). reflects how well blood can reach the brain through collateral circulation (mainly via the Circle of Willis) while the carotid artery is clamped. to assess collateral flow and need for shunt (controversial) Stump pressure < 40-50 mm Hg reflects hypoperfusion (low collateral flow) ==> Criteria for shunt placement Goal of SHUNT: + maintain CBF, decrease cerebral ischemia + Increase collateral flow with use of shunt + Decrease cerebral metabolic requirements

Answer 40

Avoid hypotension during cross clamp Avoid hypercapnia (goal 32-35) can cause "steal” phenomenon High PaCO₂ → cerebral vasodilation in normal brain regions → “steal phenomenon” (blood is diverted away from ischemic areas that cannot dilate). Avoid hyperglycemia – brain swelling. LR vs NS (avoid LR bc it contains Lactate which can convert to glucose) Hypothermia (Most avoid Bair Huggers) Pharmacologic choices

Answer 41

Hypercapnia can significantly impact cerebral circulation during CEA. CO₂ is a potent cerebral vasodilator > increasing CBF. However, hypercapnia can also lead to uneven blood distribution, worsening ischemic conditions in vulnerable brain areas. (Steal phenomenon) increased ICP: Higher CO₂ levels can elevate ICP, particularly in patients with limited cerebral autoregulation, increasing the risk of cerebral edema and compromised perfusion. Enhanced steal phenomenon: Hypercapnia can exacerbate the steal phenomenon, which can shunt blood away from already ischemic areas (in the case of CEA, from the brain region served by the narrowed carotid artery).

Answer 42

Awake Patient - Gold Standard EEG - High false-positives SSEPs - Indicates subcortical ischemia Stump Pressure - Poor sensitivity/specificity Transcranial Doppler - Assess hemodynamic ischemia, shunt function, embolic phenomenon, reperfusion syndrome

Answer 43

Determine cerebral saturation > infared light > absorption of this light by Oxygenated and deoxygenated Hgb determine overal Sat.

Answer 44

prevent thromboembolic complications 10,000u drawn up – surgeon will order dose (100u/kg) Check Blood ACT prior to giving heparin and 3-5 minutes after initial dose; then q20-30 minutes (use LR cuvettes) Prior to internal carotid artery clamping What level? must achieve 250s – 375s ==> Protamine is used to reverse heparin

Answer 45

250s – 375s

Answer 46

Surgeon decides if the patient needs a shunt during the procedure – this is something I ask during time – out Know the extent of the carotid disease in the ipsilateral carotid artery Shunts are most often utilized with severe bilateral carotid disease Inserting the Shunt: After clamping the artery, the surgeon makes a small incision in the carotid artery and inserts a flexible tube (shunt) that diverts blood around the surgical site. The shunt typically extends from one end of the clamped artery section to the other, creating a temporary blood flow channel. Removing the Shunt: Once the plaque is removed and the artery is closed, the shunt is removed before blood flow is restored.

Answer 47

Awake Intubation with minimal coughing Resident will hold pressure on neck to avoid straining Precedex is a great emergence drug – not too much Neuro exam immediately after extubation Full reversal Avoid too much versed Surgeon/Resident will do neuro exam – stick out tongue, shrug shoulders, smile, squeeze hands – each correlate to a specific cranial nerve Turn inhalational agent off early

Answer 48

Gold standard Superficial cervical plexus block: C2-C4 dermatomes Block in preop to assure completion Extensive patient preparation – must be able to lie still – warn them about drapes, pressure, talking, count to 10, state name, constant communication w patient Caution with sedation – want to assess for stroke at all times – how?

Answer 49

Superficial Cervical Plexus Block C2-C4

Answer 50

Greater stability of BP Easy cerebral monitoring Avoid intubation Avoid negative inotropic agents Fewer episodes of EEG ischemia Reduced costs

Answer 51

Patient panics Sudden loss of consciousness Onset of seizures Control of airway may be difficult Quality & timing of block

Answer 52

Assess for: Onset of new neurologic dysfunction Hemodynamic instability Respiratory insufficiency Cranial nerve deficits Hematoma Hyperperfusion syndrome

Answer 53

a rare but serious complication that can occur after CEA. It typically occurs within days to weeks following surgery. Cause: During CEA, the restored blood flow can lead to a sudden increase in blood pressure and blood flow in the brain, especially in areas that were previously under-perfused. If blood flow regulation is disrupted, it can lead to hyperperfusion syndrome. Symptoms: Symptoms often include severe headache, nausea, vomiting, confusion, visual disturbances, and, in severe cases, seizures or intracerebral hemorrhage (bleeding in the brain). ==> These symptoms can resemble a stroke Risk Factors: high blood pressure after surgery, older age, poorly controlled preoperative hypertension, and previous history of stroke or transient ischemic attack (TIA). Management and Prevention: Close monitoring of blood pressure is crucial postoperatively, as controlling blood pressure can help reduce the risk.

Answer 54

Facial Nerve (CN VII) Injury: Diagnosed by asymmetric facial movements during voluntary actions like smiling or showing teeth. Glossopharyngeal Nerve (CN IX) Injury: Identified by impaired swallowing and reduced gag reflex on one side. Vagus Nerve (CN X) Injury: Diagnosed by hoarseness, uvula deviation, and diminished palatal elevation. Spinal Accessory Nerve (CN XI) Injury: Suspected if there is unilateral shoulder droop or weakness in head rotation against resistance. Hypoglossal Nerve (CN XII) Injury: Detected by tongue deviation toward the affected side and reduced lateral tongue movement.

Answer 55

aortic aneurysm aortic dissection

Answer 56

abnormal bulging or dilation in a weakened part of the aorta. It can occur in the chest (thoracic aortic aneurysm) or abdomen (abdominal aortic aneurysm). If it ruptures, it can lead to severe internal bleeding.

Answer 57

A tear in the inner layer of the aorta’s wall, allowing blood to flow between the layers of the wall and forcing them apart. This can cause severe pain and lead to life-threatening complications if untreated.

Answer 58

75% asymptomatic Discovered by palpation of abdomen during physical exam X-ray, CT, or MRI for other conditions Pain in abdomen, chest, lower back, or groin can be indicative of impending rupture Acute pain - ruptured?

Answer 59

Age: Risk increases significantly after the age of 65. Gender: Men are more prone to aneurysms than women. Family History: A family history of aneurysms can increase risk. Smoking: Smoking damages blood vessels, and smokers have a significantly higher risk of developing aneurysms, especially abdominal ones. High Blood Pressure (Hypertension): High blood pressure increases the stress on blood vessel walls, which can weaken them over time. Atherosclerosis (Hardening of the Arteries): Plaque buildup in the arteries can weaken the aortic wall. Genetic Disorders: Certain inherited conditions, like Marfan syndrome or Ehlers-Danlos syndrome, can weaken blood vessel walls and predispose individuals to aneurysms. Infections or Inflammation: Rarely, infections or inflammatory conditions can cause or worsen aneurysms.

Answer 60

the luminal diameter of aneurysm

Answer 61

dilatation of abdominal aorta BELOW the level of the renal arteries

Answer 62

once aneurysm is >4.5-5 cm in diameter Increases by a median of 0.3 cm per year

Answer 63

Law of Laplace the theoretical basis for using the “maximum diameter criterion” for AAA rupture potential prediction. This “law” states that the stress in the AAA wall is proportional to its diameter.

Answer 64

5 Lead ECG (II, V) 2 large bore PIV (RIJ) – blood tubing A-line (dominant arm) Central Access/SG ACT TEE or PVV Fluid Warmers 500cc pressure bags Cell Saver NGT Avoid HTN on induction (esmolol)

Answer 65

Approach Vertical anterior midline*** Retroperitoneal

Answer 66

Anesthetic technique - GA Tips: Keep the patient warm Keep HR slow (avoid Tachy) Avoid anemia (HCT>25-30) Prevent HTN EBL can be large

Answer 67

Induction Agents: Typically, etomidate or propofol are used. Etomidate is preferred if the patient has a high risk of hemodynamic instability, as it has minimal impact on cardiovascular stability. Propofol can be used but requires careful titration due to its potential to cause hypotension. Opioids: Fentanyl or remifentanil are used to blunt sympathetic response, with remifentanil offering precise control due to its rapid onset and offset. Muscle Relaxants: Rocuronium may be preferred for intubation. Avoid long intubation technique.

Answer 68

Avoid Hypotension and Hypertension: Both extremes should be prevented. Hypotension can compromise perfusion to vital organs, particularly the kidneys and spinal cord, while hypertension could stress the aneurysm, risking rupture. Avoid Tachycardia: Increased heart rate adds to myocardial oxygen consumption and places more pressure on the aneurysm. Beta-blockers (esmolol or metoprolol) may be given if heart rate control is needed. Gentle Induction: Slow, controlled induction is crucial to avoid sudden hemodynamic changes. Avoid Nitrous Oxide (N2O): Nitrous oxide can increase the risk of bowel distension, which may further complicate intra-abdominal conditions.

Answer 69

Vasoactive Drugs: Prepare for possible blood pressure increases by having vasodilators on hand, such as nitroglycerin or nicardipine, which can be titrated as needed.

Answer 70

Hemodynamic Optimization: Maintain baseline hemodynamics with adequate preload and stable cardiac output. Often a fluid bolus is administered before clamping to compensate for the sudden drop in venous return. Vasoactive Drugs: Prepare for possible blood pressure increases by having vasodilators on hand, such as nitroglycerin or nicardipine, which can be titrated as needed. Communication: Coordinate with the surgical team to know the exact timing of cross-clamping. Consider increasing inhalation agent or NTG bolus just prior to cross clamping Make sure you are heparinized – check ACT Fluid management is slightly hypovolemic May give mannitol 0.5g.kg 30 minutes prior to clamping

Answer 71

infrarenal clamp

Answer 72

ABOVE the cross lamp: HYPERTENSION BELOW the cross clamp: Hypotension (80% reduction in MAP) Increases in afterload SVR MAP PAOP above the clamp PA Occlusion Pressure) CO usually decreases depending on LV function Increased cardiac oxygen consumption May experience redistribution of blood volume

Answer 73

Increase IVFs, Blood, CS slowly until closre to unclamping time. Clamp last 30-45 mins use short acting drugs Monitor urine output q30mins Ensure 1mL/kg/hr Avoid Hypovolemia, there will be large third space loss Crystalloid and blood management: cell saver and PRBC expect 600-2000 ml EBL Temperature control ACT monitoring; adjust Heparin dosing

Answer 74

Preparation for Hypotension: Anticipate and prepare for a sudden drop in blood pressure upon unclamping, as blood rushes to previously ischemic areas. Volume Loading: Give fluid boluses and optimize preload prior to unclamping to maintain systemic pressure. Calcium Administration: Consider administering calcium to counteract myocardial depression associated with reperfusion. Vasopressors on Hand: Prepare vasopressors (e.g., phenylephrine, norepinephrine) to treat severe hypotension if it occurs upon release of the clamp. Communicate with the Surgeon: The timing of the clamp release should be carefully coordinated with the surgical team to ensure readiness for hemodynamic instability. Volume load including PRBCs – call perfusion for Cardiac surgery if available prior to removing cross clamp Decrease anesthetic agent and vasodilators Anticipation rapid volume infusion – 500cc bags Know hemodynamic profile Have a specific plan Then have a 2nd and 3rd plan May unclamp all at once or one leg at a time (more common)

Answer 75

Monitor for Hypotension: Upon clamp release, be prepared to treat hypotension with vasopressors and fluid boluses. Reperfusion syndrome can lead to metabolic acidosis, hypocalcemia, and release of vasoactive substances, contributing to hypotension. Manage Acidosis and Hyperkalemia: Treat any metabolic acidosis or hyperkalemia that may occur due to the washout of ischemic metabolites. Assess Hemodynamic Status: Ensure that the patient is stable, with adequate perfusion to all organs. Optimize cardiac output and SVR to support post-clamp release circulation.

Vascular Flashcards

(102 cards)